The present disclosure relates generally to inkjet ink sets.
Secondary color inks have been added to ink sets in an effort to increase the color gamut of the printing system in which the ink sets are used. Many pigments included in secondary color inks are capable of forming images that exhibit some relatively good properties, while at the same time exhibit other relatively poor properties. As examples, some pigments generate images having good gloss and chroma, but relatively poor lightfastness (e.g., window, indoor, or outdoor) and/or poor ozonefastness; and other pigments generate images having poor gloss and chroma, but exhibit relatively good lightfastness and/or ozonefastness.
For example, secondary color inks based upon orange or red pigments generally deliver relatively good gloss and chroma. However these inks may also exhibit relatively poor lightfastness (i.e., color fade resulting from light exposure) and ozonefastness (i.e., color fade resulting form air exposure). Printed images formed from these inks tend to suffer from red, green, blue or other color density loss (i.e., fade) upon exposure to various forms of light (e.g., indoor, window, etc.) or to air over time. Alternatively, orange and orange-red inks formed with magenta and yellow pigments may be formulated to have good lightfastness. However, these inks also tend to exhibit lower chroma or pure color than inks based on a secondary color pigment. The mixed pigment inks (e.g., those formed with magenta and yellow pigments) generally do not supply additional gamut to the printing system in which they are incorporated.